The Latino health paradox intrigues researchers because it seems too good to be true: Better health outcomes for individuals with fewer resources. Why does acculturation to norms in the US, despite being accompanied by increased access to health resources and income, seem to contribute to worse health outcomes? To date, the study of acculturation and health risk has focused on behavioral factors, rather than on physiological phenotypes. There is an urgent public health need to gain insight into the cardiovascular health of Latinos, especially Mexican-Americans, an ethnic group increasingly prone to obesity-related comorbidities but understudied for cardiovascular risk factors. This interdisciplinary project will determine cardiovascular function in younger and older related adults varying in generational and immigrant status to increase understanding of the basis for the Latino acculturation paradox. 200 subjects from 100 families in East Los Angeles, including one family member from both an older and a younger generation will be enrolled. The project aims are to 1) Evaluate cardiovascular phenotypes, including arterial stiffness, endothelial function, cardiovascular risk factors and metabolic syndrome in Latino families; and 2) Evaluate the extent to which the Latino paradox holds within these families, based on their generational status and level of acculturation. Measurements will be determined at baseline and after 24 months follow-up. The primary outcome is arterial stiffness measured by applanation tonometry. Secondary outcomes include endothelial function via brachial artery flow-mediated dilation, cardiorespiratory fitness via incremental exercise test, and cardiovascular disease risk biomarkers including markers of endothelial dysfunction (soluble intracellular adhesion molecule-1 and E-selectin), oxidative stress (oxidized LDL and myeloperoxidase), systemic inflammation (C-reactive protein), and fibrinolysis. Other outcomes required to test the hypotheses include components of metabolic syndrome, diet, physical activity level and measures of acculturation. If our hypotheses are supported, more importance may be placed on taking acculturation into account when designing lifestyle change interventions designed to improve Latino cardiovascular health.